1. Field of the Invention
The present invention relates generally to xerographic copier methods and apparatus. More particularly, the present invention relates to methods and apparatus for copying original documents by selective discharge of a charged photoconductor to form a latent image and transfer of the latent image to a copy sheet which ultimately is processed to produce a visible copy of the original image. The present invention is compatible with contemporary xerographic copiers as either an add-on feature thereof or as a stand-alone copier. The present invention relates to methods and apparatus for producing multiple reduced images of original documents or the like on a single side of a copy sheet using xerographic techniques.
2. Description of the Prior Art
A significant problem in the typical office is the proliferation of information on paper and the attendant proliferation of the files needed to store that information. Development of microfiche and microfilm technologies has reduced the storage problems associated with this proliferation. While microfiche and microfilm devices achieve significant file compaction, it has only achieved limited acceptance and success in the everyday office environment. Part of the reason for this is that specialized equipment for recording and viewing is required while such equipment is generally expensive and seldom located conveniently to the typical user. Additionally the media which is usually silver halide film is expensive and generally unusable without the special magnification or viewing equipment. A relatively large number of documents are recordable on a single microfiche or microfilm but, because of the specialized recording equipment needed, the cost of such equipment and the general inconvenience of its use, recording by such devices is generally relegated to periodic processing of large batches of documents.
Xerographic copiers have developed to the point where they are now commonplace in even relatively small office environments. Such copiers frequently include image reduction structure which, in some cases, permits concurrently recording two documents in reduced size on a single side of a sheet. Such copiers also frequently include duplexing capability which allows recording reduced double copies on the opposite side so that recordation of up to four documents on a single copy sheet is possible. This is particularly attractive where the copier is capable of using plain paper copy sheets. Thus it is possible with contemporary copier devices to realize a four to one reduction in stored document volume.
While many contemporary copiers include automatic, semiautomatic and/or recirculating original document feeders, no known prior art device allows xerographic recording of multiple sequential original document images on the common surface of a single copy sheet.